Stereoretentive Halogenations and Azidations with Titanium(IV) Enabled by Chelating Leaving Groups

Lepore, Salvatore D.; Mondal, Deboprosad; Li, Song Ye; Bhunia, Anjan K.

doi:10.1002/ange.200802472

Cited by 7 publications

(2 citation statements)

References 19 publications

(2 reference statements)

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“…We began our investigation by examining the effectiveness of various leaving groups using our previously developed titanium(IV) fluoride conditions (Table 1). 12 Interestingly, our previously described nucleophile assisting leaving group (NALG) containing a diethylene oxide chelating arm (compound 2 )16 gave a similar diastereoselectivity but much poorer yield than other chelating leaving groups such as chlorosulfite 1 and 8‐sulfonylquinoline 3 . Poorer results were observed with other leaving groups (entries 4–8).…”

Section: Resultsmentioning

confidence: 97%

Reactivity of Fluoro‐Substituted Bis(thiocarbonyl) Donors with Diiodine: An XRD, FT–Raman, and DFT Investigation

Mancini

Aragoni

Bingham

et al. 2013

Chemistry An Asian Journal

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The reactions of 1,3,8,10-tetrakis(4'-fluorophenyl)-4,5,6,7-tetrathiocino[1,2-b:3,4-b']diimidazolyl-2,9-dithione (4) and molecular diiodine afforded spoke adducts with stoichiometries 4·I2 and 4·3I2 , isolated in the compound 4·3I2·xCH2Cl2·(1-x)I2 (x=0.70), and characterized by single-crystal XRD and FT-Raman spectroscopy. The nature of the reaction products was investigated under the prism of theoretical calculations carried out at the DFT level. The structural data, FT-Raman spectroscopy, and quantum mechanical calculations agree in indicating that the introduction of fluorophenyl substituents results in a lowering of the Lewis basicity of this class of bis(thiocarbonyl) donors compared with alkyl-substituted tetrathiocino donors and fluorine allows for extended interactions that are responsible for solid-state crystal packing.

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Section: Resultsmentioning

confidence: 97%

Reactivity of Fluoro‐Substituted Bis(thiocarbonyl) Donors with Diiodine: An XRD, FT–Raman, and DFT Investigation

Mancini

Aragoni

Bingham

et al. 2013

Chemistry An Asian Journal

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“…The authors proposed that the polyether chain or the quinolin‐8‐yl group coordinates the metal cation, simultaneously stabilizing the negative charge on the living sulfonate and attracting the nucleophile to effect the overall substitution. Additionally, the authors claim that the stereochemical outcome for the substitution is retention of configuration by an S N i mechanism 6b,c,7. This method has since been utilized by Kim et al.…”

Section: Introductionmentioning

confidence: 99%

Iron(III)‐Catalyzed Halogenations by Substitution of Sulfonate Esters

et al. 2011

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A novel halogenation reaction from sulfonates catalyzed by ironA C H T U N G T R E N N U N G (III) is described. The reaction can be performed as a stoichiometric or a catalytic version. This reaction provides a convenient strategy for the efficient access to structurally diverse secondary chlorides, bromides and iodides. The stereochemical course of the reaction is governed by the substrate and the experimental conditions. Secondary alcohols modified as quisylates or pysylates are substantially more reactive. Aliphatic quisylates proceed with overall inversion of configuration under catalytic conditions. Chemoselectivity in bismesylates was observed in favour of the secondary mesylate. Additionally, based on the experimental results, a possible catalytic cycle for the halogenation has been proposed.

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Efficient Procedures to Prepare Primary and Secondary Alkyl Halides from Alkanols via the Corresponding Sulfonates under Mild Conditions

et al. 2012

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The study presented herein shows that sulfonate/halide exchange can be advantageously performed in THF to avoid several side reactions such as elimination and epimerization when the reaction is performed from a chiral alkyl sulfonate or a substrate having a CH acidic chiral center. The main limitation of this procedure was found to be the conversion of secondary alkyl sulfonates to alkyl chlorides. In this case, the addition of a catalytic amount of manganese chloride clearly accelerates the rate and the efficiency of the reaction.

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Stereoretentive Halogenations and Azidations with Titanium(IV) Enabled by Chelating Leaving Groups

Cited by 7 publications

References 19 publications

Reactivity of Fluoro‐Substituted Bis(thiocarbonyl) Donors with Diiodine: An XRD, FT–Raman, and DFT Investigation

Reactivity of Fluoro‐Substituted Bis(thiocarbonyl) Donors with Diiodine: An XRD, FT–Raman, and DFT Investigation

Iron(III)‐Catalyzed Halogenations by Substitution of Sulfonate Esters

Efficient Procedures to Prepare Primary and Secondary Alkyl Halides from Alkanols via the Corresponding Sulfonates under Mild Conditions

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